.book_id {
  position: relative;
  text-align: center;
  height: 80px;
  margin-top: 10%;
  background-color: #b7dccf;
}
.book_id input {
  text-align: center;
  margin-top: 25px;
  width: 280px;
  height: 30px;
  font-size: 17px;
}
.button {
  text-align: center;
  margin-top: 7%;
  font-size: 20px;
}

.button button {
  width: 120px;
  height: 35px;
  background-color: #eee;
  border: none;
  padding: 5px 10px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 17px;
}

.button button:hover {
  background-color: #cfd8dc;
  color: #af6967;
}

.button button:disabled {
  background-color: #eee;
  color: #aaa;
  cursor: auto;
}
.tip {
  position: relative;
  text-align: center;
  margin-top: 1%;
  color: red;
}
